Petroleum Chemistry

The process of deasphalted oil thermal cracking in the presence of catalysts formed from oil-soluble Fe, Mo, Ni, and Co acetylacetonates is studied. It is shown that the used catalysts substantially change physicochemical properties of the obtained fractions. For the tested systems the structure–property relationship is ascertained and reasons behind its appearance and correlation between this relationship and process results are considered. It is found that Fe acetylacetonate (500 ppm) and Co acetylacetonate (50 and 500 ppm) show promise for further investigations.

Cobalt-molybdenum-containing thiosalts with different composition of the sulfonium cation are prepared. The activities of sulfide catalysts in situ synthesized on their basis in the hydrogenation of substituted naphthalenes are compared. It is shown that the sulfonium cation composition affects the morphology of the sulfide particles and the phase composition of the catalyst. It is demonstrated that the conversion of model alkyl-substituted bicyclic aromatic hydrocarbons is higher in the presence of the catalyst prepared from the phenylsulfonium thiosalt.

A hybrid catalyst is synthesized using ruthenium nanoparticles deposited on a nanospherical mesoporous polymer. Catalytic properties are studied in guaiacol hydrogenation at a temperature of 200–250°С and a hydrogen pressure of 5.0 MPa. Effect of solvent and catalytic additives on the reaction is investigated. It is shown that the synthesized catalyst exhibits the highest activity in guaiacol hydrodeoxygenation in the two-phase system water/n-dodecane and when the reaction is carried out in the presence of scandium triflate.

Unsupported palladium catalysts are synthesized by the ex-situ and in-situ reduction from emulsions of a precursor solution in cyclohexane. It is shown that the presence of the polymer—nitrile–butadiene rubber and butadiene–styrene rubber—in cyclohexane affects the morphology of catalyst particles. When synthesized in the presence of the polymer, the catalyst has a grapelike structure formed by ball-shaped agglomerates of palladium particles with a diameter of about 20 nm. Introduction of the polymer contributes to the integration and retention of palladium particles in the polymer network, hampers the agglomeration of particles, and facilitates their reduction. The catalytic properties of the obtained systems in the butadiene–styrene rubber hydrogenation are studied. The optimum catalyst concentration is 1 wt % Pd per polymer, and the optimum weight ratio palladium : nitrile–butadiene rubber in the synthesis stage is 1 : 10. It is advisable to perform the synthesis in situ. The catalytic activity persists during two cycles of use, after which regeneration is required. For comparison, the activity of the commercial palladium catalyst 2% palladium on activated carbon (PC) is estimated under the same conditions. It is demonstrated that in terms of activity the synthesized unsupported catalysts surpass PC. The thermal stability of the original and hydrogenated rubbers is studied by differential scanning calorimetry.

Unsupported phosphide catalysts of composition Ni₂P and CoP are prepared in situ in the reaction medium from oil-soluble precursors in the course of hydrodeoxygenation of palmitic and stearic acids. The obtained catalysts are characterized by X-ray powder diffraction and X-ray photoelectron spectroscopy; they show high activity in the hydrodeoxygenation of model substrates. After 6 h of the hydrodeoxygenation reactions, the conversion of palmitic acid reaches 93 and 92% and the conversion of stearic acid is as high as 94 and 91% in the presence of nickel phosphide and cobalt phosphide, respectively. It is shown that the catalyst formed in situ can be isolated and recycled.

Treatment conditions (oxidation, number of activation procedures) of a polymer template based on poly(ethylene terephthalate) track-etched membranes (PET TeMs) on the efficiency of the electroless deposition of copper, the structure of the synthesized copper nanotubes, and their catalytic activity in the liquid-phase reduction of p-nitrophenol are studied. It is shown that oxidative premodification contributes to an increase in the catalytic activity of the composite membrane by 20% compared with a sample synthesized in accordance with the standard procedure (etched PET TeM, single activation). In addition, it is found that the repeated implementation of the sensitization and activation stages leads to an increase in the reaction rate constant by 35 and 15% in the case of the etched and oxidized membranes, respectively. The properties of the catalysts in the temperature range of 16–35°C are studied; the activation energy E_a is calculated. The lowest E_a value is obtained for a sample synthesized in an unmodified matrix: electroless deposition into the polymer template without additional oxidative modification makes it possible to synthesize composite catalysts exhibiting relatively low catalytic activity; however, membranes of this type remain active in five test runs (p-nitrophenol conversion and reaction rate constant decrease by 26 and 44%, respectively).